High Temperature Adsorption Isotherms on Equilateral Triangular Terraces

The adsorption isotherms on infinitely long equilateral triangular terraces are obtained at high temperature. Within the context of a lattice-gas model, the computations are conducted for terraces with an increasing number $M $of atomic sites in width using long double precision arithmetic. The entropy per site divided by Boltzmann's constant reaches a maximum of ln2 at half coverage for all values of $M$, and there are (3$M-$4)/4$M$ first-neighbors per site and (3$M-$6)/4$M$ second-neighbors per site. All possible occupational configurations of the terraces are obtained for arbitrary width $M$ at half coverage.